Abstract: Objective:To detect the blood drug concentration of ginsenosides Rg1 in different feeding cycles by high performance liquid chromatography(HPLC) for determining the feeding cycle in the production of rabbit ginseng serum.Methods:The C18 column(4.6 mm×150 mm, 5 μm) was used, the Methanol-0.1% phosphate(60:40) was the mobile phase of ginsenosides Rg1, and the detection wave-length was 203 nm.Results:With the prolonging of feeding cycle, the blood drug concentration of ginsenosides Rg1 increased proportionally, the concentrations of 7 days, 14 days and 21 days were significantly higher than the concentrations of 3 days(P<0.01), the difference between 21 days and 14 days was not statistically significant(P>0.05).Conclusions:The HPLC is simple, accurate and reproducible, which can provide the experimental evidence in determining the feeding cycle of serum test, and effectively control the quality of ginseng.